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Sunday, September 18, 2011

Improvements in MARSOC Uniforms

The guys over at Kitup! have had some great coverage on the problems plaguing the Marine Special Operations Command and their new Flame Resistant Crye Uniforms in Woodland used in Afghanistan.

This carried over into additional observations with the US Army having the same problems with their FR ACU Pants in OCP. Military Times has reported that they the MARSOC has found a quick fix by changing the FR thread used for stitching to a non flame resistant cotton thread.

Now we are no textile experts and there are many can play into fabric failing under the stress of heavy combat use that both Marines and Soldiers put them through, but it has already been reiterated that the seams were not the only problem and the inherent make up of the materials is what is causing tearing out in the field.

Looking at some basic specifications of the Lenzing FR that makes up 64% of the Defencer M material from TenCate, which is utilized by the the United States Marine Corp and US Army to make their FR Uniforms, one can see the potential failings under certain conditions. Testing the tenacity of a fiber shows how well it will hold up under stress.

You can see the dry tenacity and wet tenacity (fiber introduced to liquid) figures below as provided by Lenzing. At quick glance you can see that in general given different densities, the Lenzing FR fiber is half as strong when wet. Cotton has an expected dry tenacity of around 24-36 and can even increase in strength when wet (Source: Natural Fibers, Plastics, and CompositesTable 1)

Titer/dtex

(cutlength/mm)

TenacitycN/tex

Elongation %

Wet TenacitycN/tex

1.7

40

24

14

12

2.2

38/51

24

15

12

3.3

51/75/90

22.5

15.5

11

3.3

75+90

22.5

15.5

11

5.5

60

20

22

11

8.9

80/120

16

22

8

Lenzing FR is a viscose fiber like Rayon that is derived from wood cellulose (i.e. pulp). It of course goes through a process that makes it in to the Flame Resistant, Moisture Wicking, and Heat Blocking end product that it ends up. But like other viscose fibers it retains moisture (hence moisture wicking) very effectively with a retention rate of up to double that of Cotton (See Last Source).

Of course we don't have Mr. Wizard on staff, but with quick deduction, if you get a sweaty Special Ops Marine or Soldier in particularly wet conditions, you can easily have some major moisture absorption going down, thus reducing the strength of the fibers that make up the majority of the Defender M Material. Assuming that the same Lenzing FR material was previously used in the thread that held the seams is being replaced, this could remedy the problem at major stress points. However, it is noted in the Marine Times Article "After flame-retardant uniforms get soaked with sweat, they can become brittle upon drying, causing cracks and tears".

Clearly Lenzing or TenCate are not novices like us in the field of fiber manufacturing and its use in textiles. After all 24% of the Defender M material is a para-aramid, while lacking in comfort has a very high break strength (think Kevlar). It can have a tenacity of up to 3-4 times that of cotton if not more. These same properties are in polyester and nylon on a much smaller strength scale and also for military fabrics. Para-Aramid fibers also have flame resistant properties which build on the overall focus of providing ultimate safety to our troops.

In "Combat Pants Rushed to Afghanistan" by Christian Loweit was reported that the US Army is already rushing Improved ACU Pants to soldiers which are made from Defender M material that is reinforced with Rayon, which is another viscose fiber that presumably is replacing some of the Lenzing FR. It also includes a Rip-Stop Weave. This is supposed to provide an 40% increase in strength.

Perhaps, TenCate has it dialed in this time for the Army, but why is the same tact not be taken by MARSOC. Creation of uniforms that hold up to military specifications and are able to be printed with the needed camouflage patterns really comes down to science, which includes a lot of trial and error. It is no accident that a relative few "large" manufacturers handle the task of outfitting the different U.S. Military services. A lot of research and testing go into finding the best fabrics for the task at hand and once the find an ultimate solution, it can be easy for different services to utilize the same technology which is also highly protected with patents.

No finger point seems to be going down at the moment, but continued improvements are certainly a regular affair in all respects to military uniforms. It is a waist to leg cuff coverage with all aspects taken into consideration. Let's just hope the need to remain "unique" doesn't get in the way of having the best clothing possible.